Final answer:
The Excalibur projectile is designed to self-destruct if it does not acquire adequate GPS signal or experiences a reliability failure in flight, to prevent unintended targets from being threatened.
Step-by-step explanation:
In the event the Excalibur projectile does not acquire adequate GPS signal, or experiences a reliability failure in flight, the round is designed to self-destruct. This self-destruction mechanism is included to prevent the projectile from going off course and posing a threat to unintended targets. The self-destruct feature ensures that the round will not continue to fly if it loses GPS signal or encounters a problem, ensuring safety.